1. Field of the Invention
The invention relates to a valve for regulating flow of coolant fluid between a combustion engine and a radiator in an automotive vehicle.
2. Description of the Prior Art
Internal combustion engines for automotive vehicles generate heat from the combustion of fuel and friction between the many moving components within the engine, such as the between the engine block and the pistons. An engine-driven impeller propels coolant fluid between flow paths formed within the engine block and a heat sink or radiator exposed to ambient airflow passing over the surface of the radiator for carrying the heat away from the engine block Hoses are typically used to carry coolant fluid between the engine block and the radiator.
Typically, a wax valve or thermostat is coupled between the engine block and the radiator to control the flow of coolant fluid from the engine block to the radiator. Below a predetermined temperature, the thermostat is closed to restrict coolant fluid flow from the engine block to the radiator, which expedites warming of the engine. Above the predetermined temperature, a wax element within the thermostat expands proportionally in response to the rising coolant fluid temperature to mechanically engage and open a valve within the thermostat to allow coolant fluid to flow from the engine block to the radiator. In the radiator, the coolant fluid from the engine is cooled by heat exchange with ambient airflow passing over the surface of the radiator. The cooled coolant fluid passes from the radiator to the engine block and the coolant fluid is again heated by the combustion cycle and friction generated within the engine. The valve is spring biased closed so that within a range of temperatures around the predetermined temperature, the valve opening varies in size roughly in proportion to the coolant fluid temperature. However, wax thermostats are generally slow to respond to engine block temperature and are susceptible to failure due to clogging by contaminates commonly born within the coolant fluid due to corrosion within the engine block and radiator.
It remains desirable to provide a thermostat or valve that can be actively opened and closed to allow or restrict the flow of coolant fluid between the engine block and radiator in response to a wider range of engine variables and states over conventional wax thermostats. Further, it remains desirable to provide a valve that is resistant to the contaminants in the coolant fluid.